Counterweighted top brushes for carwash brushes and other implements are well-known in the prior art. In general, a typical top brush installation includes vertical support columns on opposing sides of a wash lane. The vertical columns provide pivot points for a pair of pivot arms. A brush is mounted between the arms at one end and a counterweight is mounted at the opposite end. Because both arms are one-piece structures, synchronized movement on the brush and the counterweight in opposite directions is inherent. This arrangement, however, can be problematic in car wash systems having limited availability of space.
U.S. Pat. No. 5,713,092, “Counterweighted Vehicle Laundry Top Brush and Position Control System”, issued Feb. 3, 1998 shows a space-saving brush and counterweight arrangement wherein the top brush and the counterweights are carried by separate support arms and both sets of arms are on the same side of the pivot axis. The arms are mechanically connected by gears so that they move in opposite directions and in synchromism. Two separate counterweights are used, one on each arm and the brush support arms are slotted to permit the counterweights to pass through them on each side such that the counterweights cross below the brush.